Arsenal are considering a dramatic move for Real Madrid goalkeeper Iker Casillas as they step up their pursuit of a replacement for error-prone Wojciech Szczesny.

The Spain captain is known to be unsettled at the Bernabeu after losing his automatic place in the first team under Jose Mourinho and the Gunners are keeping a close eye on his situation.

Arsenal - shocked by their Barclays Premier League opening-day defeat by Aston Villa - are desperate to land a world-class goalkeeper and the World Cup winner and European champion would certainly fit the bill.

King of the world: Casillas lifts the World Cup (left) and Spain's first major trophy at Euro 2008 (right)

The north London club discussed moving for Chelsea
No 1 Petr Cech before the transfer window opened, believing that Thibaut
Courtois would return from his loan spell at Atletico Madrid and
replace Cech in the pecking order at Stamford Bridge.

Although
Arsene Wenger is keen on Casilllas, the stumbling block could be his
price. Casillas is 32 and ever-prudent Arsenal do not want to pay big
money for a move knowing full well they cannot sell him on.

They would consider a fee of around £8million but fear Madrid would not listen to offers below the £15m mark.

Struggling: Arsenal's current No 1 Wojciech Szczesny saw Aston Villa score three past him on Saturday

Arsenal, who trained on Tuesday ahead
of their crunch Champions League play-off with Fenerbahce, have endured a
frustrating summer in the transfer markets.

Key
targets including Gonzalo Higuain, Luis Suarez and Luiz Gonzalo have
failed to arrive at the Emirates while a clear out has left Wenger's
squad looking thin on the ground.

The Gunners have also been linked with a move for QPR keeper Julio Cesar but the Brazilian has claimed he is happy to remain with the Championship side.

Make or break: Arsenal train ahead of their crunch clash with Fenerbahce in the Champions League in Turkey